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Cloud shadows drive vertical migrations of deep-dwelling marine life
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Extant mat microbes synchronize vertical migration to a diel tempo
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Modeling water quality and cyanobacteria blooms in Lake Okeechobee: II. Dynamics of diurnal cycles and impacts of cyanobacteria diel vertical migration
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Recent Laboratory and Numerical Trailing Vortex Studies
Results from two laboratory studies and two numerical studies are presented. In the first laboratory study, measurements of the strength of vortices from a three-dimensional (3-D) model wing are presented. The measurements follow the vortices as they evolve in time from a two-dimensional (2-D) line vortex pair to the development and migration of 3-D vortex rings. It is shown that the resulting vortex rings can contain up to 40 percent of the initial vortex circulation. Thus, the formation of vortex rings may not necessarily signal the end of the wake hazard to following aircraft. In the second laboratory study, we present the results of an experiment which shows how the spanwise drag distribution affects wake-vortex evolution. In this experiment, we modified the spanwise drag distribution on a model wing while keeping the total lift and drag constant. The results show that adding drag on or near the centerline of the wing has a larger effect than adding drag at or near the wingtips. These measurements complement the results of NASA studies in the 1970s. In the first numerical study, results of 3-D numerical calculations are presented which show that the vortex Reynolds number has a significant influence on the evolution and migration of wake vortices. When the Reynolds number is large, 3-D vortex rings evolve from the initially 2-D line vortex pairs. These vortex rings then migrate vertically. When the Reynolds number is lower, the transition of vorticity from 2-D to 3-D is delayed. When the Reynolds number is very low, the vortices never transition to 3-D, and the vertical migration is significantly reduced. It is suggested that this effect may have been important in previous laboratory wake-evolution studies. A second numerical study shows the influence that vertical wind shear can have on trailing vortex evolution.
Wilson Corners Solid Waste Management Unit (SWMU) 001: 2021 Annual Long-Term Monitoring Report, Kennedy Space Center, Florida
This report presents a summary of the long-term monitoring (LTM) activities that occurred in 2021 at Wilson Corners, Solid Waste Management Unit (SWMU) 001, at Kennedy Space Center (KSC), Florida. The site is monitored under KSC’s Resource Conservation and Recovery Act (RCRA) Corrective Action Program. Adaptive site management is being utilized through ongoing assessment, design, and interim measures (IM). Annual LTM of the groundwater is also being conducted at the site. This approach also meets the requirements of Chapter 62-780, Florida Administrative Code (F.A.C.). The goal of LTM at this site is threefold: to determine groundwater flow characteristics, monitor the downgradient concentration trends, and monitor select locations internal to the groundwater plume. Every 5 years, upgradient and side-gradient monitoring wells are sampled to verify delineation. The last time this was performed was in 2015. The sampling of these wells in 2020 was replaced with the direct push technology (DPT) investigations completed in October 2020 and April 2021. This DPT groundwater data was presented in an Advance Data Package (ADP) in September 2021 and discussed in the Implementation Work Plan (IWP) dated November 2021 for installation of an air sparge (AS) system. Based on results from groundwater sampling activities performed during the previous reporting period, including the 2020 and 2021 DPT groundwater sampling, it was determined that the LTM sampling plan was no longer meeting the goal of LTM because delineation was not verified. The 2021 LTM sampling plan was modified to include the sampling of monitoring wells located around the perimeter of the low concentration plume (LCP); the area with concentrations of contaminants of concern [COCs] greater than Groundwater Cleanup Target Levels [GCTLs]), and sampling of 10 monitoring wells proposed for installation (April 2021 KSC Remediation Team (KSCRT) Meeting, Decision 2104-D32). The modified LTM plan received team consensus at the September 2021 KSCRT Meeting (Decision Number 2109-D03), and sampling of the existing monitoring wells was completed in December 2021. The proposed monitoring wells are planned for installation in late 2022, concurrent with ongoing IM construction activities. December 2021 LTM data was presented at the May 2022 KSCRT Meeting, and activities are summarized in this report. The activities presented in this report include the December 2021 groundwater gauging of 42 monitoring wells and sampling of 44 monitoring wells. During the December 2021 event, the low flow sampling method was used, and samples were analyzed for a select list of volatile organic compounds (VOCs), including 1,1,2-trichloro-1,2,2-trifluoroethane (Freon 113). The following conclusions can be made based on the 2021 LTM results: - In December 2021, groundwater flow for the site was generally to the west at all intervals. This is generally consistent with historical observations at the site, with the exception of a southwest and southeast flow component observed at 34 to 48 feet below land surface (bls). - The vertical extent of VOCs was historically delineated by monitoring wells screened greater than 48 feet bls. The results from the two vertical extent monitoring wells, WILC-MW0078 (screened 65 to 70 feet bls) and WILC-MW0130 (screened 56 to 66 feet bls) that were sampled during the 2021 LTM indicate that groundwater vinyl chloride (VC) concentrations in both wells were greater than the GCTL. The Remediation Team has previously agreed to delay deeper DPT investigations in this area to prevent the creation of additional pathways for vertical migration. - The LCP continues to extend both horizontally, predominantly to the west, and vertically beyond the current monitoring well network, with some retraction observed to the southeast. Evaluation of this data combined with data from the 2020 and 2021 DPT sampling event indicate that the LCP encompasses an estimated 20.7 acres based on an expanded sampling area, as compared to the 2020 LCP footprint of 17.0 acres. - Freon 113 was not detected above GCTLs during the 2021 LTM event. Based on groundwater sampling activities performed in 2021, including April 2021 DPT groundwater sampling, the following recommendations are provided: - Perform the next LTM sampling event, targeted to occur in 2023, concurrently with the IM baseline sampling prior to AS system installation; - Include sampling from nine monitoring wells that are planned to be installed in late 2022, concurrent with upcoming IM construction activities. Installation of one deep vertical well, screened 70 to 80 feet bls, will be delayed to prevent the creation of an additional pathway for vertical migration; - Continue to sample under the modified annual LTM plan as presented in Table 4-1 concurrently with IM baseline sampling; and - Once the AS system install and start-up is complete, select monitoring wells from the LTM program will transition into the performance monitoring plan, and LTM will be temporarily discontinued. Performance monitoring will be performed quarterly, and the monitoring well network will be evaluated following the first performance monitoring sampling event.
Marine biology. Volume III - Ecology of invertebrates
Marine invertebrate ecology - sampling techniques, food intake, quality of food, seasonal aspects of food and breeding, algal mutualism, plankton, vertical migration, and benthos
The relation between isotopic composition of argon and carbon in natural gases
The methods and results of determination of the argon and carbon isotope compositions of hydrocarbon gases of Mezozoic complexes of Western Siberia are presented. Based on the Ar-36, Ar-40, C-12, C-13 content of the various deposits and on the presumed mechanisms of entry of these isotopes into the deposits, it is concluded that formation of natural gas in some deposits included vertical migration from a lower complex.
Preferred Negative Geotactic Orientation in Mobile Cells: Tetrahymena Results
For the protozoan species Tetrahymena a series of airplane experiments are reported, which varied gravity as an active laboratory parameter and tested for corresponding changes in geotaxic orientation of single cells. The airplane achieved altemating periods of low (0.01 g) and high (1.8 g, g = 980 cm/s) gravity by flying repeated Keplerian parabolas. The experimental design was undertaken to clearly distinguish gravity from competing aerodynamic and chemical gradients. In this way, each culture served as its own control, with gravity level alone determining the orientational changes. On average, 6.3% of the Tetrahymena oriented vertically in low gravity, while 27% oriented vertically in high-gravity phases. Simplified physical models are explored for describing these cell trajectores as a function of gravity, aerodynamic drag, and lift. The notable effect of gravity on turning behavior is emphasized as the biophysical cause of the observed negative geotaxis in Tetrahymena. A fundamental investigation of the biological gravity receptor (it it exists) and improved modeling for vertical migration in important types of ocean plankton motivate the present research.
Investigating the Impact of UV Radiation on High-Altitude Shallow Lake Habitats, Life Diversity, and Life Survival Strategies: Clues for Mars' Past Habitability Potential?
We present data and results from an ongoing project of astrobiological high-altitude expeditions investigating the highest and least explored perennial lakes on Earth in the Bolivian and Chilean Andes, including several volcanic crater lakes nearing and beyond 6,000 m in elevation. In the next five years, they will provide the first integrated long-term astrobiological characterization and monitoring of lacustrine environments and their biology for such altitude. These extreme lakes are natural laboratories. They provide the field data missing beyond 4,000 m to complete our understanding of terrestrial lakes and biota. Research on the effects of UV has been performed in lower altitude lakes and models of UV flux over time are being developed. Lakes showing a high content of dissolved organic material (DOM) shield organisms from UV. DOM acts as a natural sunscreen as it influences the water transparency, therefore is a determinant of photic zone depth. In sparsely vegetated alpine areas, lakes are clearer and offer less protection from UV to organisms living in the water. Transparent water and high UV irradiance may maximize the penetration and effect of UV radiation. Shallow-water communities in these lakes are particularly sensitive to UV radiation. The periphyton can live on various susbtrates. While on rocks, it includes immobile species that cannot seek low UV refuges unlike sediment-dwelling periphyton or alpine phytoflagellates which undergo vertical migration. Inhibition of algal photosynthesis by UV radiation has been documented in laboratory and showed that phytoplankton production is reduced by formation of nucleic acid lesions or production of peroxides and free oxygen radicals. of peroxides and free oxygen radicals. Our project is providing the field data that is missing from natural laboratories beyond 4,000 m and will complement the vision of the effects of UV on life and its adaptation modes (or lack thereof).
Reduced ENSO Variability at the LGM Revealed by an Isotope-Enabled Earth System Model
Studying the El Nino Southern Oscillation (ENSO) in the past can help us better understand its dynamics and improve its future projections. However, both paleoclimate reconstructions and model simulations of ENSO strength at the Last Glacial Maximum (LGM; 21 ka B.P.) have led to contradicting results. Here we perform model simulations using the recently developed water isotope-enabled Community Earth System Model (iCESM). For the first time, model-simulated oxygen isotopes are directly compared with those from ENSO reconstructions using the individual foraminifera analysis (IFA). We find that the LGM ENSO is most likely weaker comparing with the preindustrial. The iCESM suggests that total variance of the IFA records may only reflect changes in the annual cycle instead of ENSO variability as previously assumed. Furthermore, the interpretation of subsurface IFA records can be substantially complicated by the habitat depth of thermocline-dwelling foraminifera and their vertical migration with a temporally varying thermocline.
Wilson Corners, Solid Waste Management Unit 001(SWMU 01) 2023 Annual Long-Term Monitoring Report
This report presents a summary of the long-term monitoring (LTM) activities that occurred in 2023 at Wilson Corners, Solid Waste Management Unit 001, at Kennedy Space Center (KSC), Florida. Annual LTM of groundwater is being conducted at the site. Based on results from groundwater sampling activities performed during the 2019 through 2020 LTM reporting period and the 2020 and 2021 DPT groundwater sampling, it was determined that the LTM sampling plan was no longer meeting the goal of LTM because delineation was not verified and the installation of an air sparge (AS) system to treat the area of the High Concentration Plume was recommended. The AS System was installed in late 2022 and early 2023. System start-up activities were initiated in April 2023. Following system startup, several site wells required retrofitting to equip wellheads for withstanding the air pressure released from air sparge wells during system operation. Some site wells also required repair or abandonment, and replacement. Survey of location and top-of-casing of newly installed monitoring wells was combined with scheduled AS system survey activities and was completed in January 2024. The activities presented in this report include the February and April 2023 LTM monitoring well installations; March and April 2023 LTM and performance monitoring well water level gauging and sampling; November 2023 LTM well retrofits and repairs; a summary of December 2023 LTM well abandonments and installations (complete site well abandonment activities will be presented under a separate cover); and January 2024 LTM well survey. During the March and April 2023 sampling events, the low-flow sampling method was used, and samples were analyzed for a select list of volatile organic compounds. In March 2023, groundwater flow for the site was generally to the west was generally consistent with historical observations at the site. The Low Concentration Plume (LCP) continues to extend both horizontally and vertically beyond the terminal depth of the current monitoring well network. Data, inclusive of the 2023 LTM and baseline performance monitoring sampling events, indicate that the LCP encompasses an estimated 19.5 acres, compared to the 2021 LCP footprint, inclusive of the 2020 and 2021 DPT sampling events of 20.7 acres. The vertical extent of VOCs was historically delineated by monitoring wells screened greater than 48 feet below land surface (bls). The results from the three vertical extent monitoring wells screened below 48 feet bls that were sampled during the 2023 LTM indicate that groundwater vinyl chloride concentrations in these three wells are greater than the GCTL. As presented in the 2021 Long-Term Monitoring Report (NASA 2022), the KSCRT agreed to delay deeper investigations in this area to prevent the creation of additional pathways for vertical migration. Based on groundwater sampling activities performed in 2023, recommendations are to perform the next annual LTM sampling event, scheduled for April 2024 and to conduct quarterly performance monitoring of the AS System. The current selection of monitoring wells in the recommended 2024 LTM plan will provide an adequate data set for monitoring groundwater plume behavior; however, the LTM monitoring well network will be evaluated and refined based on 2024 LTM and year one performance monitoring data.
Satellite Ocean Colour: Current Status and Future Perspective
Spectrally resolved water-leaving radiances (ocean colour) and inferred chlorophyll concentration are key to studying phytoplankton dynamics at seasonal and inter-annual scales, for a better understanding of the role of phytoplankton in marine biogeochemistry; the global carbon cycle; and the response of marine ecosystems to climate variability, change and feedback processes. Ocean colour data also have a critical role in operational observation systems monitoring coastal eutrophication, harmful algal blooms, and sediment plumes. The contiguous ocean-colour record reached 21 years in 2018; however, it is comprised of a number of one-off missions such that creating a consistent time-series of ocean-colour data requires merging of the individual sensors (including MERIS, Aqua-MODIS, SeaWiFS, VIIRS, and OLCI) with differing sensor characteristics, without introducing artefacts. By contrast, the next decade will see consistent observations from operational ocean colour series with sensors of similar design and with a replacement strategy. Also, by 2029 the record will start to be of sufficient duration to discriminate climate change impacts from natural variability, at least in some regions. This paper describes the current status and future prospects in the field of ocean colour focusing on large to medium resolution observations of oceans and coastal seas. It reviews the user requirements in terms of products and uncertainty characteristics and then describes features of current and future satellite ocean-colour sensors, both operational and innovative. The key role of in situ validation and calibration is highlighted as are ground segments that process the data received from the ocean-colour sensors and deliver analysis-ready products to end-users. Example applications of the ocean-colour data are presented, focusing on the climate data record and operational applications including water quality and assimilation into numerical models. Current capacity building and training activities pertinent to ocean colour are described and finally a summary of future perspectives is provided.
A molecular and isotopic study of the organic matter from the Paris Basin, France
Thirteen Liassic sedimentary rocks of increasing depth and three petroleums from the Paris Basin were studied for 13C/12C isotopic compositions and biological markers, including steranes, sterenes, methylphenanthrenes, methylanthracenes, and triaromatic steroids. The isotopic compositions of n-alkanes from mature sedimentary rocks and petroleums fall in a narrow range (2%), except for the deepest Hettangian rock and the Trias petroleum, for which the short-chain n-alkanes are enriched and depleted in 13C, respectively. Most of the molecular parameters increase over the 2000-2500 m depth range, reflecting the transformation of the organic matter at the onset of petroleum generation. In this zone, carbonate content and carbon isotopic composition of carbonates, as well as molecular parameters, are distinct for the Toarcian and Hettangian source rocks and suggest a migration of organic matter from these two formations. Two novel molecular parameters were defined for this task: one using methyltriaromatic steroids from organic extracts; the other using 1-methylphenanthrene and 2-methylanthracene from kerogen pyrolysates. The anomalous high maturity of the Dogger petroleum relative to the maturity-depth trend of the source rocks is used to estimate the minimal vertical distance of migration of the organic matter from the source rock to the reservoir.
Methods of Sensing Land Pollution from Sanitary Landfills
Major cities are congested and large sites suitable for landfill development are limited. Methane and other gases are produced at most sanitary landfills and dumps. These gases may migrate horizontally and vertically and have caused fatalities. Monitoring these gases provides data bases for design and construction of safe buildings on and adjacent to landfills. Methods of monitoring include: (1) a portable combustible gas indicator; and (2) glass flasks valved to allow simultaneous exhaust of the flask and aspiration of the sample into the flask. Samples are drawn through tubing from probes as deep as twenty-five feet below the surface.
Aura/MLS Observes and SD-WACCM-X Simulates the Seasonality, Quasi-Biennial Oscillation and El Niño-Southern Oscillation of the Migrating Diurnal Tide Driving Upper Mesospheric CO Primarily Through Vertical Advection
This work uses 17 years of upper mesospheric carbon monoxide (CO) and temperature observations by the Microwave Limb Sounder (MLS) on-board the Aura satellite to present and explain the seasonal and interannual variability of the migrating diurnal tide (DW1) component of upper mesospheric CO. This work then compares these observations to simulations by the Specified Dynamics – Whole Atmosphere Community Climate Model with Ionosphere/Thermosphere eXtension (SD-WACCM-X). Results show that, for all seasons, MLS CO local-time perturbations peaks above 85 km and has a latitude structure resembling the (1,1) mode in temperature. On the other hand, SD-WACCM-X DW1 also peaks above 85 km and has a latitude structure resembling the (1,1) mode but it simulates 2 local maximum of the (1,1) mode between 85 km and 92 km. Despite the differences in altitude structure, a tendency analysis and the adiabatic displacement method revealed that, on seasonal and interannual timescales, observed and modelled CO’s (1,1) component can be reproduced solely using vertical advection. It was also found that both observed and modelled CO’s (1,1) component contains interannual oscillations with periodicities close to that of the Quasi-biennial Oscillation and the El Niño–Southern Oscillation. From these results, this work concludes that on seasonal and interannual timescales, the observed and modelled (1,1) mode affects the global structure of upper mesospheric CO primarily through vertical advection.
Aura/MLS Observes, and SD-WACCM-X Simulates the Seasonality, Quasi-Biennial Oscillation and El Nino Southern Oscillation of the Migrating Diurnal Tide Driving Upper Mesospheric Co Primarily Through Vertical Advection
This work uses 17 years of upper mesospheric carbon monoxide (CO) and temperature observations by the Microwave Limb Sounder (MLS) on-board the Aura satellite to present and explain the seasonal and interannual variability of the migrating diurnal tide (DW1) component of upper mesospheric CO. This work then compares these observations to simulations by the Specified Dynamics – Whole Atmosphere Community Climate Model with Ionosphere/Thermosphere eXtension (SD-WACCM-X). Results show that, for all seasons, MLS CO local-time perturbations peaks above 85 km and has a latitude structure resembling the (1,1) mode in temperature. On the other hand, SD-WACCM-X DW1 also peaks above 85 km and has a latitude structure resembling the (1,1) mode but it simulates 2 local maximum of the (1,1) mode between 85 km and 92 km. Despite the differences in altitude structure, a tendency analysis and the adiabatic displacement method revealed that, on seasonal and interannual timescales, observed and modelled CO’s (1,1) component can be reproduced solely using vertical advection. It was also found that both observed and modelled CO’s (1,1) component contains interannual oscillations with periodicities close to that of the Quasi-biennial Oscillation and the El Nino Southern Oscillation. From these results, this work concludes that on seasonal and interannual timescales, the observed and modelled (1,1) mode affects the global structure of upper mesospheric CO primarily through vertical advection.
Nonmigrating diurnal tides in the equatorial middle atmosphere
Data from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to extend the analysis of diurnal tides in the middle atmosphere to include the zonally symmetric and eastward propagating components. These modes show vertical and meridional structures that are generally consistent with the predictions of linear tidal theory. The zonal and meridional wind fields are calculated from the tidal temperatures. Diurnal perturbations in LIMS temperature and derived winds agree well with equinoctial model calculations. Comparisons with day-night differences of radiosonde temperature and rocket winds show qualitative agreement in vertical structure and amplitude. The zonally symmetric and eastward migrating tidal components show a higher degree of temporal variability than the sun-synchronous component. These modes at times contribute substantially to the diurnal signal in wind and temperature, with combined amplitudes equal to or in excess of the amplitude of the main migrating diurnal tide. The observed vertical phase variations suggest that their forcing may originate below the stratosphere.